Added an option to make init.g on SD run on boot.

Sprinter/Configuration.h

@@ -49,6 +49,8 @@ const bool Z_ENDSTOP_INVERT = false;
 
 // Comment out (using // at the start of the line) to disable SD support:
 #define SDSUPPORT
+// Uncomment to make Sprinter run init.g from SD on boot
+//#define SDINITFILE
 
 
 //// ADVANCED SETTINGS - to tweak parameters

Sprinter/Sprinter.pde

@@ -176,8 +176,17 @@ unsigned long stepper_inactive_time = 0;
           Serial.println("volume.init failed");
     else if (!root.openRoot(&volume)) 
           Serial.println("openRoot failed");
-    else 
-            sdactive = true;
+    else{
+          sdactive = true;
+          #ifdef SDINITFILE
+            file.close();
+            if(file.open(&root, "init.g", O_READ)){
+                sdpos = 0;
+                filesize = file.fileSize();
+                sdmode = true;
+            }
+          #endif
+    }
   #endif
   }